1) Field of the Invention
The present invention relates to a developer container for a developer supplying unit and an electrophotographic image forming apparatus.
2) Description of the Related Art
Electrophotographic apparatuses generally use powder developer called toner or carrier so as to form toner images using developing devices and create images. Since toner is consumed as images are formed, the toner which is stored in toner cartridges (developer containers) is fed to main units, and the toner cartridge which runs short of the toner is generally replaced by a new one so that new toner is supplied.
Toner supplying units (developer supplying units) require a function such that toner in toner containers is discharged securely and completely and the discharged toner is delivered to developing devices securely. Conventional toner containers require the function of discharging toner securely and completely from the toner containers.
As the toner supplying units, as shown in FIG. 8A, a device, which has a movable member 12 such as a screw or a coil spring commonly known as an auger in a toner storage container 11, is known. In the toner supplying unit, when a rotary shaft 13 of the movable member 12 is driven to be rotated, the toner in the toner storage container 11 is transported to a direction towards a discharge port 11a and is discharged form the discharge port 11a to be supplied to a developer supplying unit.
On the other hand, as shown in FIG. 8B, a device called a screw bottle 15, which uses a cylindrical toner stage container formed with spiral projections 14 on its inner periphery along a peripheral direction, is known. In this toner supplying unit, the screw bottle 15 is driven to be rotated, so that toner in the screw bottle is transported to a direction of a discharge port 15a, and is discharged from the discharge port 15a so as to be supplied to a developer supplying unit.
A system which does not have a discharge mechanism in a toner container is developed recently. A system, in which toner in a bag type soft container is pumped by a suction pump and is fed to a developing device, is already manufactured. Further, the inner toner is pumped and discharged so that a volume of the container from which the toner is discharged can be reduced (the container deflates) (see, for example, Japanese Patent Application Laid-Open No. 2001-324863 and Japanese Patent Application Laid-Open No. 2002-72649). A toner transport method of accelerating a toner storage container due to asymmetrical reciprocating motion, and moving the toner in the container to one direction by inertia so as to discharge the toner from a discharge port provided at a lower portion of the container is proposed (see, for example, Japanese Patent Application Laid-Open No. 2002-046843 and Japanese Patent Application Laid-Open No. 2002-268346).
Since toner cartridges are, however, consumable goods and used containers are generated every time of toner replacement, obviously, resource saving of toner containers is desired from a viewpoint of not only the costs but also environmental protection. Further, it is an important task for the environmental protection that manufacturers retrieve toner containers and reuse or recycle them.
In the delivery system using an auger, a member should be provided in a container and be rotated, which constitution is complicated, thereby inhibiting the resource saving and increasing the cost. In the delivery system using the screw bottle, a member is not provided in a container, and thus its constitution is simple. Since a screw groove is, however, provided to a wall of the container and the container is rotated to be used, the shape of the container is limited to a cylindrical hard bottle, thereby limiting resource saving.
Since the toner delivery system using the suction pump adopts the system in which a suction pump pumps toner in the toner container, the toner container does not require the toner discharge function, and thus a toner container which remarkably saves resources can be used. An example of such a container is a bag type flexible container made of a thin sheet.
Since an oscillating system does not require a delivery member in a container, a flexible container which saves resources can be used similarly to the system adopting the suction pump. This system has an advantage such that it can adopt a simple container shape with a large intake capacity (small dead space) such as cuboid. Since the volume of the flexible containers can be reduced, they have excellent transport efficiency at the time of retrieving used containers.
The manufacturers' work for retrieving toner containers is actually inefficient in some occasions. The occasions include ones where manufacturers' branch offices and service deposits are separated from users, and the occasion where some numbers of cartridges are retrieved. In these occasions, a retrieving system in which users send back used toner containers to the manufacturers by mail is effective. The flexible containers have an advantage such that they can be sent by ordinary mail.
However, some small amount of toner adheres to used toner containers and when the toner containers in this state are sent by mail, other postal matters could be stained by the toner, and thus the toner containers should be enclosed in bags or envelopes. Also when used toner containers are stored, they must be kept in bags or the like similarly because depositories could be stained by the toner. This work takes an effort and increases the cost, and also hands are stained by the toner during the work, or the toner scatters in the bags. Therefore, when the toner containers are taken out of the bags and are treated after retrieval, the work may become inefficient